Ground reservoir for the storage of a liquefied gas

ABSTRACT

934,030. Storing liquefied gases. CONCH INTERNATIONAL METHANE Ltd. May 24, 1962, No. 20017/62. Class 8(2). A reservoir for the storage of a liquefied gas, e.g. natural gas, methane, ethane, propane, oxygen or nitrogen, comprises a hole 1 in the surface of the earth having an impervious lining 3 to its side walls and a bottom 4 constituted by an impervious ground layer, and a thermally insulated roof 5 completely covering the hole. The ground layer may be clay or rock and the lining preferably of concrete, as shown in Fig. 1, or a metal such as aluminium, steel or stainless steel. The roof 5 is of steel and has a layer of thermal insulation 6 spaced from and attached to the roof by suspension brackets 7; the roof and insulation are built into the surface of the earth. Through the roof extend a charging conduit 8, a discharging conduit 9 fitted with a pump 10 and a gas vent 11 fitted with a pressure control device 12. The thermal insulation on the roof may be fibre glass, foam plastic such as polystyrene or polyurethane foam, paper honeycomb or perlite and the lining 3 may have on its inside and/or its outside an insulation layer which may be sealcoated with mastic. In a further embodiment, Fig 2 (not shown), the lining and roof are integral and of steel provided on the outside with a layer of insulation seal-coated with mastic, the lining and insulation layer extending into the impervious ground layer. The liner is caulked and grouted into the impermeable ground layer and a narrow space between the side walls of the hole and the insulation layer is filled with concrete or liquid cement grout. A single conduit for charging and discharging the reservoir passes through the roof. In another embodiment, Fig. 3 (not shown), the hole extends into the impervious ground layer, the lower part of the hole being of reduced diameter to provide a step into which a steel lining is caulked and grouted. The lining and roof are made from steel plates welded together. The charging and discharging conduits preferably pass through the roof by way of a trunk but may pass through tunnels in the sides of the hole.

Nov. 15, 1966 M. NACHSHEN GROUND RESERVOIR FOR THE STORAGE OF A LIQUEFIED GAS Filed Aug. 17. 1962 5 Sheets-Sheet 1 wamw Inventor Map/c5 MCHSflE/V M. NACHSHEN 3,285,014

5 Sheets-Sheet 2 F/GZ.

Nov. 15, 1966 GROUND RESERVOIR FOR THE STORAGE OF A LIQUEFIED GAS Filed Aug. 1.7, 1962 w w m Inventor Mamas/v MA we me A ttorn e y:

Nov. 15, 1966 M. NACHSHEN 3,285,014

I GROUND RESERVOIR FOR THE STORAGE OF A LIQUEFIED GAS Filed Aug. L7, 1962 3 Sheets-Sheet 3 F/G. i.

J .1 WW 1 36 WWW/y: $25 1 a Inventor Map/c5 Mam/5m y 00%, 777 floufMfM United States Patent No. 217,652 Claims priority,

application Great Britain, May 24, 1962,

20,017/ 62 5 Claims. (Cl. 61.5)

This invention concerns a reservoir for the storage of a liquefied gas in which the gas is kept in a hole in the surface of the earth which has been adapted for this purpose.

In this specification, the expression liquefied gas means liquid that boils at atmospheric pressure at a temperature below the ambient temperature, for example liquefied natural gas, methane, ethane, propane, oxygen or nitrogen.

According to the invention, a reservoir for the storage of a liquefied gas comprises a hole in the surface of the earth having an impervious lining to its side walls and a bottom consituted by an impervious ground layer; a thermally insulated roof completely covering the hole; a gas vent; and conduit means for charging or discharging the reservoir.

The invention enables advantage to be taken of widely available types of geological structure, namely pervious ground layers with impervious ground layers underneath. The impervious ground layer can be any impervious ground layer, namely an impervious clay or rock. A dried up river bed havinga layer of gravel over a layer of rock is an example of a formation where a reservoir according to the invention could be constructed. A reservoir according to the invention can be rectangular or square, but it is preferably cylindrical, and it can be very large, for example, 200 feet wide and 100 feet deep.

The hole in the surface of the occurring hole or it can be made artificially by any of various methods, for example by either excavating the hole as such or excavating a perimetric trench having a bottom constituted by an impervious ground layer, placing in the trench the lining for the side walls of the hole, and excavating earth enclosed by the lining. If desired, the hole may not merely reach but can extend into the impervious ground layer, and the extension of the hole or a lower part thereof can be narrower than the part of the hole above the impervious ground layer, so as to provide a step to support the lining and into which the lining can be caulked and grouted when necessary, for example when the lining is made from metal.

The impervious lining can be jointless or consist of sections joined together at air and liquid tight joints, and it can be of any thickness appropriate to the surrounding ground layer or layers. Preferred impervious linings are made from concrete or a suitable metal such as aluminum or steel. If desired, the lining can extend to a depth below the bottom of the hole. The lining can have on its inside or outside or both a layer of thermal insulation (for example, fibre glass, foam plastic for instance polystyrene or polyurethane foam, paper honeycomb or perlite), which can have a seal coat of, for example, mastic. The insulation can extend partly or wholly over the respective surfaces; for example, thermal insulation on the outside of the lining can extend from the top of the lining to the beginning of the impervious ground layer. As described later the thermally insulated roof can be integral with the lining and of the same material.

When the lining is made from metal, it is desirable that the bottom of the lining be caulked and grouted into the impervious ground layer. Any space between the lining or the insulation, if present on the outside of the lining,

earth can be a naturally vit can be of any appropriate 3,285,914 Patented Nov. 15, 1966 "ice and the side walls of the hole should be kept as small as possible, and is for example filled up with concrete or liquid cement grout.

When the lining is made from concrete, it can be made by any of various methods, for example by a trenching method. One such method, method A, comprises excavating a perimetric trench having a bottom constituted by an impervious ground layer, pumping out any water present in the trench, supporting the sides of the trench if necessary, and filling up the trench with concrete and allowing it to harden into a monolithic structure; supports (for example, concrete or timber) used to support the sides of the trench can be removed as the concrete is added or they can be left in place. A second suitable method, method B, is similar to method A, but, instead of using supports to support the sides of the trench, the trench is kept full with a heavy mud (for example, drilling mud), and concrete is injected into the trench, thereby displacing the heavy mud. Whatever method is used, reinforcements can be embedded in the concrete during construction of the lining.

The lining can also be made of a metal, suitable metals are for example stainless steel or steel. A possible method for its construction comprises excavating the hole in the surface of the earth as such, pumping out any water present in the hole, supporting the sides of the hole if necessary, and fabricating the lining in situ. When a metal lining is used it will in most cases be necessary to reinforce it by suitable webs fixed to the inside or the outside of the lining.

The thermally insulated roof can be jointless or consist of sections joined together at air or liquid tight joints, and

thickness. The thermally insulated roofs can be made from concrete or from metal (for example, aluminum or steel). The roof can have on its inside or outside or both a layer of thermal insulation (for example, fibre glass, foam plastic for instance polystyrene or polyurethane foam, paper honeycomb or perlite), which can have a seal coat of, for example, mastic. If desired, the insulation on the inside of the roof can be suspended therefrom by brackets, the space between the roof and the insulation adding to the insulation properties of the roof as a whole. The roof can be integral with the impervious lining and of the same material, thereby avoiding problems of the anchorage of the roof. The roof can be joined to the impervious lining in situ, if desired.

The gas vent leads gas produced in the reservoir to a disposal point or recovery plant, and is preferably fitted with a pressure control device for controlling the pressure of gas in the reservoir. It is conveniently fitted in the roof.

The conduit means can be of any suitable type; for example, a single conduit leading to the bottom of the hole in the surface of the earth can be used for charging or discharging the reservoir. Discharge of the reservoir can be effected by any suitable pumping system for example by a gas lift system, or by a submerged pump connected to an outlet conduit. The conduit means can pass through the roof, preferably through a trunk, or they can pass through tunnels in the sides of the hole up to the surface of the earth.

The invention will now be further described with reference to the accompanying drawings, in which FIGURES 1, 2 and 3 are vertical sections of different cylindrical reservoirs according to the invention.

In FIGURE 1, hole 1 of the reservoir has been constructed in surface of the earth 2 by constructing a concrete lining 3 according to method B described above, and excavating earth enclosed by the lining. The bottom of the hole is constituted by impervious clay 4. The hole is completely covered by a steel roof 5 with a layer of .polysure of gas in the reservoir.

tinued over the outside of the roof 39.

styrene foam 6 suspended therefrom by brackets 7. The space between the roof and the foam adds to the insulation properties of the roof as a whole. The roof and the insulation are built a small way into the surface of the earth. Through the roof, pass a charge conduit 8 and a discharge conduit 9, both extending almost to the bottom of the hole. The discharge conduit is fitted with a pump 10. A gas vent 11 in the roof allows exit of gas produced in the reservoir, and is fitted with a pressure control device 12 or controlling the pressure of gas in the reservoir. The optimum liquid level is shown at 13.

In FIGURE 2, hole 15 of the reservoir has been constructed by direct excavation in surface of the earth 16. The side walls of the hole have a steel lining 17 .provided on its outside with a layer of polyurethane foam 18 having a seal coat of mastic 19. The lining extends into rock 20, and its lower part is caulked and grouted into the rock, which constitutes the bottom of hole 15. The narrow space between the side walls and the foam is filled up with concrete 21 or liquid cement grout. Integral with the lining is a steel roof 22. The lining 17 and the roof 22 are made from steel plates welded together. The layer of polyurethane foam on the otuside of the lining is continued over the outside of the roof. Passing through the roof is a single conduit 23, which can be used either for charging the reservoir through branch 24 or for discharging the reservoir through branch 25, dis-charge being effected by a gas lift system. A gas vent 26 in the roof allows exit of gas produced in the reservoir, and is fitted with a pressure control device 27 for controlling the pres- The optimum liquid level is shown at 28.

In FIGURE 3, hole 30 of the reservoir has been constructed by direct excavation in surface of the earth 31, and it not merely reaches but extends into rock 32. The rock line is shown at 33. The lower part of the extension of the hole is of reduced diameter, so as to provide a step into which the lower part of a steel lining 35 is side walls of the hole, of its outside with a layer of polystyrene foam 36 having a seal coat of mastic 37. The space between the side walls and the foam and the lining, where not covered by foam, is filled up with concrete 38. Integral with the lining is a steel roof 39. The lining 35 and the roof 39 are made from steel plates welded together. The layer 36 of polystyrene foam on the outside of the lining 35 is con- Passing through the roof is a single conduit 40, which can be used either for charging the reservoir through branch 41 or for discharging the reservoir through branch 42, discharge being allows exit of gas produced in the reservoir, and is fitted with a pressure control device 44 for controlling the pressure of gas in the reservoir. The optimum liquid level is shown at 45.

I claim:

1. A reservoir for the storage of liquefied gas, at a temperature far below ambient temperature, comprising a fluid-impervious fabricated enclosure wall which is structurally rigid at all ambient temperatures completely lintight sealing engagement with a fluid-impervious natural ground stratum, constituting the bottom of the reservoir for direct retaining and supporting engagement with liquid gas to be stored in said reservoir; said wall defining with said stratum a fluid-impervious, water-free storage reservoir; a fiuid-and-vapor tight roof, substantially at the surface of the earth, completely covering the storage reservoir and sealing the interior thereof from the ambient atmosphere, a gas vent in fluid communication with said storage reservoir having a pressure control device therein for controlling the vapor pressure within the storage reservoir, and conduit means in fluid communication with said storage reservoir for charging into and discharging from the storage reservoir a liquefied gas.

2. A reservoir as claimed in claim 1, in which the wall is made of concrete.

3. A reservoir as claimed in claim 1, in which the storage reservoir extends into the impervious ground stratum.

impervious ground stratum, so as to provide a step for the bottom of the wall.

5. A reservoir as claimed in claim 3 in which the wall is made of steel.

References Cited by the Examiner UNITED STATES PATENTS 1,467,121 9/1923 Smith et al 52-249 1,561,260 11/1925 Mallery 61.5 X 2,332,227 10/1943 Jackson 52-l69 2,333,315 11/1943 Klin-gberg 61-.5 2,777,295 1/1957 Bliss et al. 52-249 2,880,593 4/1959 Johnson et al 61.5 X 2,961,840 11/1960 Goldtrap 6l'.5 X

2,962,183 11/1960 Rill et al. 3,047,184 7/ 1962 Van Bergen et al. 52-469 X 3,076,317 2/1963 La Fave 52-249 3,092,933 6/1963 Closner 52224 3,151,416 10/1964 Eakin et al 52-169 X 3,195,310 7/1965 Schroeder 61.5 3,205,665 9/1965 Van Horn 61.5

EARL J. WITMER, Primary Examiner. 

1. A RESERVOIR FOR THE STORAGE OF LIQUIFIED GAS, AT A TEMPERATURE FAR BELOW AMBIENT TEMPERATURE, COMPRISING A FLUID-IMPERVIOUS FABRICATED ENCLOSURE WALL WHICH IS STRUCTURALLY RIGID AT ALL AMBIENT TEMPERATURES COMPLETELY LINING THE SIDES OF A HOLE IN THE GROUND AND EXTENDING DOWN SUBSTANTIALLY FROM THE SURFACE OF THE GROUND INTO FLUIDTIGHT SEALING ENGAGEMENT WITH A FLUID-IMPERVIOUS NATURAL GROUND STRATUM, CONSTITUTING THE BOTTOM OF THE RESERVOIR FOR DIRECT RETAINING AND SUPPORTING ENGAGEMENT WITH LIQUID GAS TO BE STORED IN SAID RESERVOIR; SAID WALL DEFINING WITH SAID STRATUM A FLUID-IMPERVIOUS, WATER-FREE STORAGE RESERVOIR; A FLUID-AND-VAPOR TIGHT ROOF, SUBSTANTIALLY AT THE SURFACR OF THE EARTH, COMPLETELY COVERING THE STORAGE RESERVOIR AND SEALING THE INTERIOR THEREOF FROM THE AMBIENT ATMOSPHERE, A GAS VENT IN FLUID COMMUNICATION WITH SAID STORAGE RESERVOIR HAVING A PRESSURE CONTROL DEVICE THEREIN FOR CONTROLLING THE VAPOR PRESSURE WITHIN THE STORAGE RESERVOIR, AND CONDUIT MEANS IN FLUID COMMUNICATION WITH SAID STORAGE RESERVOIR FOR CHARGING INTO AND DISCHARGING FROM THE STORAGE RESERVOIR A LIQUEFIED GAS. 